Proliferative lesions of vitreoretinal juncture, in both the posterior and peripheral fundus, occur as spontaneous sequelae of ocular and systemic disease, and as complications of ocular surgical procedures. The spectrum of proliferative lesions in the posterior fundus includes simple epiretinal membranes (usually subtle and asymptomatic), surface wrinkling retinopathy (sometimes with significant visual loss) and complex fibrous or vascular proliferations (which often culminate in tractional retinal detachment and irreversible blindness). Degenerative lesions of the peripheral fundus (primarily tractional) are the most common cause of rhegmatogenous retinal detachment. The proposed project will study in man the ultrastructural features of those factors (developmental, senescent and disease related) which predispose the vitreoretinal juncture to degenerative or proliferative lesions, and in experimental animals similar factors under controlled laboratory conditions. As a primary goal, the investigations will attempt to elucidate the pathogenesis of each of proliferative lesions in the above spectrum and their interrelationships (e.g. in diabetes). Another no-less-important goal is an understanding of the degenerative lesions of the vitreoretinal juncture which predispose to rhegmatogenous retinal detachment. It is expected that information from this project will contribute to a better pathogenic understanding of lesions of the vitreoretinal juncture and, thereby, to improved prophylactic and therapeutic management of patients. BIBLIOGRAPHIC REFERENCES: Ultrastructural Features of Posterior Vitreous Detachment, R.Y. Foos, Albrecht v. Graefes Arch klin exp. Ophthal, 196:103-111 (Sept.) 1975. Acute Retrolental Fibroplasia, R.Y. Foos, Albrecht v. Graefes Arch klin exp. Ophthal, 195:87-100, 1975.